Goal: Existing Conditions Modeling

Status of Use Document: Draft

Phase(s): Planning and Design


Objective(s):

[_] Document existing building for historical use
[_] Detailed design coordination
[_] During the design phase for location information (different from interference detection)

Description:

A process in which a project team develops a 3D model of the existing conditions for a site, facilities on a site, or a specific area within a facility. This model can be developed in multiple ways depending on what is desired and what is most efficient. Once the model is constructed, it can be queried for information, whether it be for new construction or a modernization project.

Potential Benefits:

[_] 3D visualization
[_] Aids in future modeling and 3D design coordination
[_] Provides documentation of environment for future uses, e.g. renovation or historical documentation
[_] Aids in construction analysis for complex situations
[_] Enhances the efficiency and accuracy of existing conditions documentation

Levels of Detail Considerations:

  • Extent of the existing facility and environment that you wish to model, e.g. modeling the exterior enclosure of the buildings, all the interior spaces, the detailed MEP systems, the existing site conditions, and detailed modeling of architectural details for historical record
  • Existing conditions modeling from measurements and photographs
  • Existing conditions modeling from 3D laser scanning

Team Competencies Required:

  • Modeling from existing condition information, e.g. photos, measurements, or 3D laser scanning information
  • 3D laser scanning (if used)
  • 3D laser scanning point cloud translation into objects (if used)

Characteristics in order to substantiate BIM use:

Project -
Organization -
Environment -
Contract -
Process -

Potential Modeling Methods:

  • Measuring by person followed by modeling within a 3D or BIM modeling application
  • 3D laser scanning, potentially followed by conversion of the corresponding 3D point cloud to an information rich BIM

Potential Outputs:

  • 3D geometric model (define file format)
  • 3D point cloud data with no parametric information
    • Can be adjusted to define systems and/or objects with some effort

Legal / Commitment Considerations:

  • Guarantee of accuracy may be a significant concern, particularly if there are small tolerances for future component installations
  • A legal precedent is missing for BIM models
  • Terminology in contracts state that the model is a basis to work from and architect is not responsible for inconsistencies in the model
  • Project quality is controlled in house like drawing reviews

Additional Resources:

General Description: N/A


Quantitative Studies: N/A


Case Study Examples:

  • St. Elizabeth: laser scan of entire site

Software Applications:

  • Revit
  • ArchiCAD
  • 3D imaging software
    • LADAR
    • LIDARS
    • Triangulation based
  • Lyca Cyclone
  • Bentley CloudWorx
  • VRMesh

References:

  • 3D Laser Scanning. GSA BIM Guide Series 3